From 79ffc3e056788fab6fb0350bb47e45943866da70 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Thu, 20 Jan 2022 18:11:20 -0800
Subject: [PATCH] Expand PlayerItemMendEvent

---
 .../minecraft/world/entity/ExperienceOrb.java.patch  | 12 ++++++++----
 .../org/bukkit/craftbukkit/entity/CraftPlayer.java   |  5 +++--
 .../bukkit/craftbukkit/event/CraftEventFactory.java  |  4 ++--
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/paper-server/patches/sources/net/minecraft/world/entity/ExperienceOrb.java.patch b/paper-server/patches/sources/net/minecraft/world/entity/ExperienceOrb.java.patch
index da00e3e03b..2e0228c9d3 100644
--- a/paper-server/patches/sources/net/minecraft/world/entity/ExperienceOrb.java.patch
+++ b/paper-server/patches/sources/net/minecraft/world/entity/ExperienceOrb.java.patch
@@ -215,12 +215,15 @@
                  }
              }
  
-@@ -266,12 +359,20 @@
+@@ -266,12 +359,23 @@
              ItemStack itemstack = ((EnchantedItemInUse) optional.get()).itemStack();
              int j = EnchantmentHelper.modifyDurabilityToRepairFromXp(player.serverLevel(), itemstack, amount);
              int k = Math.min(j, itemstack.getDamageValue());
 +            // CraftBukkit start
-+            org.bukkit.event.player.PlayerItemMendEvent event = CraftEventFactory.callPlayerItemMendEvent(player, this, itemstack, optional.get().inSlot(), k);
++            // Paper start - mending event
++            final int consumedExperience = k > 0 ? k * amount / j : 0;
++            org.bukkit.event.player.PlayerItemMendEvent event = CraftEventFactory.callPlayerItemMendEvent(player, this, itemstack, optional.get().inSlot(), k, consumedExperience);
++            // Paper end - mending event
 +            k = event.getRepairAmount();
 +            if (event.isCancelled()) {
 +                return amount;
@@ -229,14 +232,15 @@
  
              itemstack.setDamageValue(itemstack.getDamageValue() - k);
              if (k > 0) {
-                 int l = amount - k * amount / j;
+-                int l = amount - k * amount / j;
++                int l = amount - k * amount / j; // Paper - diff on change - expand PlayerMendEvents
  
                  if (l > 0) {
 +                    // this.value = l; // CraftBukkit - update exp value of orb for PlayerItemMendEvent calls // Paper - the value field should not be mutated here because it doesn't take "count" into account
                      return this.repairPlayerItems(player, l);
                  }
              }
-@@ -291,6 +392,24 @@
+@@ -291,6 +395,24 @@
      }
  
      public static int getExperienceValue(int value) {
diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 809b1ead09..0dda38dcd7 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -1865,11 +1865,12 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
                 handle.serverLevel(), itemstack, amount
             );
             int i = Math.min(possibleDurabilityFromXp, itemstack.getDamageValue());
-            org.bukkit.event.player.PlayerItemMendEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerItemMendEvent(handle, orb, itemstack, stackEntry.get().inSlot(), i);
+            final int consumedExperience = i * amount / possibleDurabilityFromXp; // Paper - taken from ExperienceOrb#repairPlayerItems
+            org.bukkit.event.player.PlayerItemMendEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerItemMendEvent(handle, orb, itemstack, stackEntry.get().inSlot(), i, consumedExperience);
             i = event.getRepairAmount();
             orb.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DESPAWN);
             if (!event.isCancelled()) {
-                amount -= i * amount / possibleDurabilityFromXp;
+                amount -= consumedExperience; // Use previously computed variable to reduce diff on change.
                 itemstack.setDamageValue(itemstack.getDamageValue() - i);
             }
         }
diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java b/paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
index ec5c16f64d..8fba20a2ff 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -1284,10 +1284,10 @@ public class CraftEventFactory {
         return event;
     }
 
-    public static PlayerItemMendEvent callPlayerItemMendEvent(net.minecraft.world.entity.player.Player entity, net.minecraft.world.entity.ExperienceOrb orb, net.minecraft.world.item.ItemStack nmsMendedItem, net.minecraft.world.entity.EquipmentSlot slot, int repairAmount) {
+    public static PlayerItemMendEvent callPlayerItemMendEvent(net.minecraft.world.entity.player.Player entity, net.minecraft.world.entity.ExperienceOrb orb, net.minecraft.world.item.ItemStack nmsMendedItem, net.minecraft.world.entity.EquipmentSlot slot, int repairAmount, int consumedExperience) { // Paper - Expand PlayerItemMendEvent
         Player player = (Player) entity.getBukkitEntity();
         org.bukkit.inventory.ItemStack bukkitStack = CraftItemStack.asCraftMirror(nmsMendedItem);
-        PlayerItemMendEvent event = new PlayerItemMendEvent(player, bukkitStack, CraftEquipmentSlot.getSlot(slot), (ExperienceOrb) orb.getBukkitEntity(), repairAmount);
+        PlayerItemMendEvent event = new PlayerItemMendEvent(player, bukkitStack, CraftEquipmentSlot.getSlot(slot), (ExperienceOrb) orb.getBukkitEntity(), repairAmount, consumedExperience); // Paper - Expand PlayerItemMendEvent
         Bukkit.getPluginManager().callEvent(event);
         return event;
     }